Sockets or clips having multiple fingers or beams are commonly used in electrical connectors designed to mate with the pins of integrated circuits and other electronic devices. As is known, such sockets are formed in multi-stage or progressive stamping dies. Following in the stamping process, the sockets are typically tumbled to reduce burrs and to polish and improve the surface finish. The sockets may also be heat treated or plated using a tumbling process.
Although sockets having three fingers or beams are known, many sockets in use today have a greater number of beams, for example, four or six.
Generally speaking, the more beams that a socket has the more costly it is to manufacture and the more difficult it is to control the manufacturing process. Also, sockets with greater numbers of beams tend to result in higher insertion and withdrawal forces during the use of the socket. Such forces can be decreased by controlling beam configuration and material. But this is typically accompanied by a decrease in per beam normal forces because those forces would be distributed over four or six points. Since normal force is a factor determining Hertzian stress, a decrease in normal force results in a reduction of Hertzian stress and therefore in a deterioration of electrical performance, most notably, higher and less stable contact resistance. Thus, additional beams do not necessarily result in better electrical performance.
Moreover, the beams of sockets having, for example, six beams, are more susceptible to failure during the insertion process of pressing the socket into a sleeve. Beams that break off can lodge in between the sleeve and the connecting pin resulting in product failure.
It has been found that sockets employing three beams can provide lower insertion/withdrawal forces while preserving excellent electrical characteristics. Thus, when mated to the round, square or rectangular pins of integrated circuit or pin grid array devices, such three beam sockets create high Hertzian stress connections. Three beam sockets are also less costly to manufacture because the manufacturing process is easier to control. Still further, the beams of three beam sockets are less prone to break off during use.
Nevertheless, existing three beam sockets do have one drawback. The spaces separating the beams of three beam sockets are usually large enough to allow the parts to interlock or tangle during fabrication processes in which the parts are tumbled. Such tangling results when the tip of one socket enters and lodges in the space between adjacent beams of another socket. This not only creates a feeding problem in subsequent assembly processes, but results in a loss of product and production, since it is not economical to untangle the parts. Although tangling can arise with sockets having more than three beams, this is not usually the case because the spaces between the beams of such sockets tend to be smaller.
Thus, it is an overall object of the present invention to provide a multiple beam socket which obviates the problem of interlocking or tangling of the parts during tumbling.